133 research outputs found

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    More than competition: exploring stakeholder identities at a grassroots cause-related sporting event

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    The purpose of this paper is to (a) explore stakeholder identities of a grassroots cause-related sporting event; and (b) gain a better understanding of how identities are related to stakeholder development, support of the event, and future intentions. We used a mixed methods research design that consisted of two studies: qualitative followed by quantitative. Study 1 explored stakeholder identities and how they are related to stakeholder development and support of the event, and Study 2 examined how future intentions regarding attendance, donations, and sponsor support differ based on levels of stakeholder identity. Sports marketing and non-profit management literature streams as well as identity theory and social capital theory informed our studies. The National Kidney Foundation Surf Festival was selected because it is a grassroots cause-related sporting event with financial success over the last two decades. In addition, a surf contest, an action sport, is a unique sport setting in the nonprofit sector, which offers insight to marketers seeking to target subcultures. The findings of the qualitative study revealed three identities relevant to participants: sport subculture, community, and cause. A framework emerged from the data that illustrated how these identities unite together to generate social capital, which is linked to effective volunteer and sponsorship management. Quantitative analysis through survey data provided further evidence of the impact of identification with a cause-related sport activity on consumer outcomes. Results indicated attendees with high surf-related identity are more likely to attend future Surf Festivals, have higher intentions to donate to the cause, and have higher sponsor purchase intentions compared to those with low self-identity with the sport subculture. The conclusion discusses implications, framing the findings through the intersection of the sports marketing and non-profit sector industries, and provides suggestions for future research.Ye

    Vertebral Pneumaticity in the Ornithomimosaur Archaeornithomimus (Dinosauria: Theropoda) Revealed by Computed Tomography Imaging and Reappraisal of Axial Pneumaticity in Ornithomimosauria

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    Among extant vertebrates, pneumatization of postcranial bones is unique to birds, with few known exceptions in other groups. Through reduction in bone mass, this feature is thought to benefit flight capacity in modern birds, but its prevalence in non-avian dinosaurs of variable sizes has generated competing hypotheses on the initial adaptive significance of postcranial pneumaticity. To better understand the evolutionary history of postcranial pneumaticity, studies have surveyed its distribution among non-avian dinosaurs. Nevertheless, the degree of pneumaticity in the basal coelurosaurian group Ornithomimosauria remains poorly known, despite their potential to greatly enhance our understanding of the early evolution of pneumatic bones along the lineage leading to birds. Historically, the identification of postcranial pneumaticity in non-avian dinosaurs has been based on examination of external morphology, and few studies thus far have focused on the internal architecture of pneumatic structures inside the bones. Here, we describe the vertebral pneumaticity of the ornithomimosaur Archaeornithomimus with the aid of X-ray computed tomography (CT) imaging. Complementary examination of external and internal osteology reveals (1) highly pneumatized cervical vertebrae with an elaborate configuration of interconnected chambers within the neural arch and the centrum; (2) anterior dorsal vertebrae with pneumatic chambers inside the neural arch; (3) apneumatic sacral vertebrae; and (4) a subset of proximal caudal vertebrae with limited pneumatic invasion into the neural arch. Comparisons with other theropod dinosaurs suggest that ornithomimosaurs primitively exhibited a plesiomorphic theropod condition for axial pneumaticity that was extended among later taxa, such as Archaeornithomimus and large bodied Deinocheirus. This finding corroborates the notion that evolutionary increases in vertebral pneumaticity occurred in parallel among independent lineages of bird-line archosaurs. Beyond providing a comprehensive view of vertebral pneumaticity in a non-avian coelurosaur, this study demonstrates the utility and need of CT imaging for further clarifying the early evolutionary history of postcranial pneumaticity

    Glutathione Reductase Targeted to Type II Cells Does Not Protect Mice from Hyperoxic Lung Injury

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    Exposure of the lung epithelium to reactive oxygen species without adequate antioxidant defenses leads to airway inflammation, and may contribute to lung injury. Glutathione peroxidase catalyzes the reduction of peroxides by oxidation of glutathione (GSH) to glutathione disulfide (GSSG), which can in turn be reduced by glutathione reductase (GR). Increased levels of GSSG have been shown to correlate negatively with outcome after oxidant exposure, and increased GR activity has been protective against hyperoxia in lung epithelial cells in vitro. We tested the hypothesis that increased GR expression targeted to type II alveolar epithelial cells would improve outcome in hyperoxia-induced lung injury. Human GR with a mitochondrial targeting sequence was targeted to mouse type II cells using the SPC promoter. Two transgenic lines were identified, with Line 2 having higher lung GR activities than Line 1. Both transgenic lines had lower lung GSSG levels and higher GSH/GSSG ratios than wild-type. Six-week-old wild-type and transgenic mice were exposed to greater than 95% O2 or room air (RA) for 84 hours. After exposure, Line 2 mice had higher right lung/body weight ratios and lavage protein concentrations than wild-type mice, and both lines 1 and 2 had lower GSSG levels than wild-type mice. These findings suggest that GSSG accumulation in the lung may not play a significant role in the development of hyperoxic lung injury, or that compensatory responses to unregulated GR expression render animals more susceptible to hyperoxic lung injury

    Alterations of the Thioredoxin System by Hyperoxia: Implications for Alveolar Development

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    Alterations in vascular endothelial growth factor (VEGF) contribute to alveolar simplification seen in animal models of bronchopulmonary dysplasia, and VEGF expression is redox regulated by thioredoxin (Trx)-1 in other diseases. The present studies tested the hypothesis that exposure to 85% O2 negatively impacts the Trx1 system and VEGF expression in the lungs of newborn mice. There was no effect of fraction of inspired oxygen on lung Trx1 or Trx reductase-1 protein levels; however, lung Trx1 protein was predominantly oxidized in the lungs of newborn mice exposed to 85% O2 by 24 hours of exposure. In room air (RA), lung Trx interacting protein (Txnip) levels decreased developmentally through Day 7 (1.0 ± 0.06 [Day 1] vs. 0.49 ± 0.10 [Day 3] vs. 0.29 ± 0.03 [Day 7]; P < 0.01), whereas VEGF expression increased (1.25 ± 0.16 [Day 1] vs. 4.35 ± 1.51 [Day 3] vs. 13.23 ± 0.37 [Day 7]; P < 0.01). Newborn mice exposed to 85% O2 had no developmental decrease in Txnip protein levels and a delayed increase in VEGF protein levels. Lung Txnip and VEGF protein levels were different than in corresponding RA controls at Day 3, before the detection of lung morphologic abnormalities in our model. Txnip and VEGF protein levels were inversely correlated in both the RA and hyperoxia-exposed groups (n = 18; R = −0.66; P = 0.003). In conclusion, oxidation of Trx1 and sustained Txnip expression in the lungs of newborn mice exposed to 85% oxygen is likely to severely attenuate normal Trx1 function. The inverse correlation of Txnip with VEGF expression suggests that decreased Trx1 function contributes to the observed lung developmental abnormalities
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